Abstract: Methods, systems, and devices are disclosed for fabricating clean, oxidation-free nanoparticles of electrically conducting metals and alloys using spark erosion techniques. In one aspect, a method includes dispersing bulk pieces of an electrically conducting material in a dielectric fluid with mechanical vibrations within a container; generating an electric field using electrodes in the dielectric fluid using by an electric pulse, in which the electric field creates a plasma in a volume existing between the bulk pieces that locally heats the bulk pieces to form structures within the volume, the dielectric fluid quenching the structures to form nanoparticles, and filtering the nanoparticles through a screen including holes of a size allowing nanoparticles of the size or smaller to pass through the screen to a region in the container, in which the dielectric fluid inhibits oxidation of the surface of the nanoparticles.

Abstract: A method of preparing thermoelectric material particles, the method comprising: disposing a first electrode and a second electrode in a dielectric liquid medium, wherein the first and second electrodes each comprise a thermoelectric material; applying an electrical potential between the first and second electrodes to cause a spark between the first and second electrodes to provide a vaporized thermoelectric material at a sparking point of at least one of the first and second electrodes; and cooling the vaporized thermoelectric material with the dielectric liquid medium to prepare the thermoelectric material particles.

Abstract: Methods, systems, and devices are disclosed for fabricating clean, oxidation-free nanoparticles of electrically conducting metals and alloys using spark erosion techniques. In one aspect, a method includes dispersing bulk pieces of an electrically conducting material in a dielectric fluid with mechanical vibrations within a container; generating an electric field using electrodes in the dielectric fluid using by an electric pulse, in which the electric field creates a plasma in a volume existing between the bulk pieces that locally heats the bulk pieces to form structures within the volume, the dielectric fluid quenching the structures to form nanoparticles, and filtering the nanoparticles through a screen including holes of a size allowing nanoparticles of the size or smaller to pass through the screen to a region in the container, in which the dielectric fluid inhibits oxidation of the surface of the nanoparticles.

Abstract: A method of preparing thermoelectric material particles, the method comprising: disposing a first electrode and a second electrode in a dielectric liquid medium, wherein the first and second electrodes each comprise a thermoelectric material; applying an electrical potential between the first and second electrodes to cause a spark between the first and second electrodes to provide a vaporized thermoelectric material at a sparking point of at least one of the first and second electrodes; and cooling the vaporized thermoelectric material with the dielectric liquid medium to prepare the thermoelectric material particles.

Abstract: A single layer film is deposited onto a substrate at room temperature from two sources, one source being a magnetic material, the other being a non-magnetic or weakly-magnetic material. The film is annealed for predetermined time in order to induce phase separation between the magnetic clusters and the non-magnetic matrix, and to form stable clusters of a size such that each magnetic particle, or cluster, comprises a single domain and has no dimensions greater than the mean free path within the particle.

Abstract: A single layer film is deposited onto a substrate at room temperature from two sources, one source being a magnetic material, the other being a less-magnetic material. The film is annealed for predetermined times in order to induce phase separation between the magnetic clusters and the less-magnetic matrix, and to form stable clusters of a size such that each magnetic particle, or cluster, comprises a single domain and has no dimensions greater than the electron spin flip mean free path within the particle. The creation of two magnetic phases makes it possible to establish exchange coupling between the phases so that a relatively low saturation field is required to induce GMR.

Abstract: A single layer film is deposited onto a substrate at room temperature from two sources, one source being a magnetic material, the other being a non-magnetic or weakly-magnetic material. The film is annealed for predetermined time in order to induce phase separation between the magnetic clusters and the non-magnetic matrix, and to form stable clusters of a size such that each magnetic particle, or cluster, comprises a single domain and has no dimensions greater than the mean free path within the particle.